CHROMOSOMAL MUTATIONS - PRÓF 2

- structural aberrations - numerical aberrations

chromosomal mutations are subdivided into:

the exchange of the broken fragments between two chromosomes - usually, there are no phenotypical manifestation in carriers

describe Reciprocal translocation:

SKOÐA EINKENNI

describe a person with down syndrome:

loss of part of chromosome

describe deletion

the fragment form one homologous chromosome is attached to another homologous chromosome

describe duplication

two breaks of chromosome, the part between breaks is reinserted into its original place but in reverse order

describe inversion:

there is monosomy of the long arm and trisomy of the short arm

describe isoXp in females:

transverse division of chromosomes during mitotic meta-anaphase - The chromosome consists of two copies of either the long (q) arm or the short (p) arm

describe isochromosome mutation

two broken ends of chromosome can stick together and form a ring

describe ring chromosome mutation

- 47 XX, + 21 - 47 Xy, +21

describe the autosomal chromosomes in human with Down syndrome:

- 47 XX, +18 - 47 XY, +18

describe the autosomal chromosomes in human with Edward´s syndrome:

- 47 XX, +13 - 47 XY, +13

describe the autosomal chromosomes in human with Patau syndrome:

- 46XX,5p- - 46 XY, 5p- the short arm on chromosome 5 has been deleted

describe the chromosomes in humans with cri du chat syndrome:

- 47 XXY - 48 XXXY - 49 XXXXY

describe the gonosomal chromosomes in human with Klinefelter syndrome:

47 XXX

describe the gonosomal chromosomes in human with Superfemale syndrome:

45 X (45 X0)

describe the gonosomal chromosomes in human with Turner syndrome:

47 XYY

describe the gonosomal chromosomes in human with supermale syndrome:

translocation occuring between two acrocentric chromosomes where they attach one to another - end to end - short arms of both chromosomes fuse together

describe the robertsonian translocation

ring chromosome mutation of chromosome 20

epilepsy is the result of

50% of live born children die in the first month

how are the death incidences in pataus syndrome?

- only 50% live to 2 months - only 5-10% will survive their first year of life

how are the death incidences of live born infants with edwards syndrome

95% die in uterus

how are the death incidences of the Edwards syndrome?

1:6.000

how are the incidences of patau syndrome?

1:1.000

how are the incidences of turner syndrome?

1:2.000

how are the incidences of turner syndrome?

t(2;9)

how do we describe if there is a reciprocal translocation between chromosome 2 and 9 ?

by reciprocal t(8;14) translocation of the c-myc oncogene

how does the Burkitt´s lymphoma form?

it is usually the result from non disjunction during mitosis in the zygote

how is mosaicism formed?

1:6.000

how many incidences are there of edwards syndrome?

1:800

how many incidinces are there of down syndromes?

meiosis I and meiosis II

meiotic non disjunction can happen in

1. trisomy 21 - down syndrome 2. trisomy 13 - patau syndrome 3. trisomy 18 - edwards syndrome

name autosomal aneuploidies in humans:

- non disjunction of chromosomes during meiotic anaphase 1 or 2 - non disjunction of chromosomes during mitotic anaphase

name causes of aneuploidy:

- abnormal diploid egg - fertilisation of egg by two sperms

name causes of polyploidy:

- it can destroy the genes function - it can alter the expression of the gene - it can create a hybrid gene

name results of translocation mutation

mosaicism

name the disease:

1. turner syndrome 2. klinefelter syndrome 3. superfemale 4. supermale

name the gonosomal aneuplodies in humans:

duplication

name the mutation

isochromosome

name the mutation

paracentric inversion

name the mutation

pericentric inversion

name the mutation

reciprocal translocation

name the mutation

ring chromosome

name the mutation

robertsonian translocation

name the mutation

A = terminal deletion b = interstitial deletion

name the mutations (upper and lower)

- polyploidy - aneuploidy

name the numerical aberrations:

1) leptotene 2) zygotene 3) pachytene 4) diplotene 5) diakinesis.

name the stages of prophase:

- deletion - inversion - duplication - isochromosomes - ring chromosomes - translocation

name the structural aberrations:

normal = 2n missing = 2n - 1 (or -2, -3) multiple state = 2n + 1 (or +2,+3)

name the types of aneuploidy:

1) reciprocal 2) Robertsonian 3) unbalanced

name three types of translocations:

there is monosomy of the short arm and trisomy of the long arm

result of isoXq

- terminal deletion - interstitial deletion

types of deletion

1) pericentric inversion 2) paracentric inversion

types of inversion

the translocated genes can be under the control of different promoters and enhances

under what control are the translocated genes ?

Trisomies and monosomies are two types of chromosomal abnormalities

what are monosomy and trisomy?

the short arms of the chromosomes fusing in the Robertsonian translocation - they are usually lost during the translocation

what are the minute fragments?

this can result in down syndrome

what are the result of the robertsonian translocation

acute myeloid leukaemia

what can duplication result in ?

A Robertsonian translocation can result in trisomy 14 or trisomy 21. Trisomy 21 is also known as Down syndrome.

what can form down syndrome?

in philadelphia chromosome which is the chromosome abnormality that causes chronic myeloid leukemia (CML)

what can formation of hybrid gene by translocation result in ?

opitz kaveggia syndrome

what can inversion result in ?

Turner syndrome in females or tumour cells

what can isochromosomes result in ?

isochromosomes

what can result in Turner syndrome?

duplication

what can result in acute myeloid leukaemia?

epilepsy

what can ring chromosomal formation of chromosome 20 result in ?

A genetic hybrid carries two different alleles of the same gene

what is a hybrid gene?

the normal chromosome complement consists of 46 chromosomes, including the 2 sex chromosomes. Also known as the karyotype.

what is a normal chromosome complements?

means that there is an extra copy of part of a chromosome - the genes in that segments are present in triplicate

what is a partial trisomy?

it is a numerical chromosomal aberration multiplying of chromosomal sets - f.x three or four sets of chromosomes

what is a polyploidy?

numerical chromosomal aberration where there are different number of chromosomes in diploid set, f.x 47 or 48 chromsomes

what is aneuploidy ?

folds in the inner corner of the eyes - mongolism

what is epicanthic skin folds?

ishochromosome of the short arm of the X chromosome

what is isoXp?

isochromosome of the long arm of the X chromosome

what is isoXq?

simian crease

what is it called when a person has a single palmar fold

the first stage of the prophase of meiosis, during which each chromosome becomes visible as two fine threads (chromatids).

what is leptotene?

Failure of two members of a chromosome pair (healthy) to separate from one another during meiosis, causing both chromosomes to go to a single daughter cell

what is meiotic non disjunction ?

disjunction in mitosis caused by failure in separation of chromatids

what is mitotic non dis-juction ?

it is a condition in which an individual has cells with different chromosome complements (Mosaicism is when a person has 2 or more genetically different sets of cells in their body)

what is mosaicism?

inversion which does not involve the centromere, only one arm of the chromosome is affected

what is paracentric inversion?

it is the same as a deletion and means that a segment of chromosome has been lost - there is a single copy of genes in that segment, instead of a pair

what is partial monosomy ?

inversion around the centromere, both arms of chromosome are affected

what is pericentric inversion ?

The Ph chromosome is an abnormally short chromosome 22 that is one of the two chromosomes involved in a translocation (an exchange of material) with chromosome 9.

what is philadelphia chromosome?

trisomy X

what is superfemale?

this protein formed by the translocation mutation resulting in philadelphia chromosome causes CML (chronic myeloid leukemia) cells to grow and divide out of control

what is the bcr-abl protein ?

cri du chat syndrome

what is the result of the deletion of the short arm of chromsome 5

carriers can form abnormal gametes - can form burkitt´s lymphoma

what is the result of the reciprocal translocation

transfer of a piece of one chromosome to another non homologous chromosome

what is translocation mutation ?

triploidy = 3n, 23 x 3 = 69 chromosomes tetraploidy = 4n, 23 x 4 = 92 chromosomes - norma somatic cell = 2n

what is triploidy and tetraploidy?

monosomy X

what is turner syndrome?

it occurs when a child inherits a chromosome with extra or missing genetic material from a parent with a balanced translocation

what is unbalanced translocation ?

the second stage of the prophase of meiosis, following leptotene, during which homologous chromosomes begin to pair.

what is zygotene?

translocated genes forming altered gene expression - under the control of different promoters and enhances

what mutation results in Burkitt´s lymphoma?

deletion fo the short arm of chromosome 5

what mutation results in cri du chat syndrome?

only the 2n chromosomal composition

what type of polyploidy is compatible with life?

they often occur together - they may be the result of a balanced translocation of inversion in one of the parents

when do the partial monosomies and partial trisomies occur?

during mitosis of zygote or during embryogenesis

when does mitotic non dis-disjunction occur?